Latching device



Oct. 14, 1958 W.M. PATTERSON 2,355,799

LATCHING DEVICE Original Filed Dec. 4; 1951 IN V EN TOR. WALLACE M. PATTERSON ATTORNEY United States Patent O LATCHING DEVICE Wallace M. Patterson, Penn Wynne, Pa., assignor to Sellers Injector Corporation, Philadelphia, Pa., a corporation of Pennsylvania Original application December 4, 1951, Serial No. 259,769, new Patent No. 2,715,909, dated August 23, 1955. Divided and this application March 5, 1953, Serial No. 340,459

3 Claims. (Cl. 74-527) This invention relates to restraining or latch mechanisms by which the relatively delayed movement of a movable member subjected to increasing pressure conditions is translated into quick action by means of sudden release. One use of the combination illustrating the invention is shown in Patent No. 2,715,909, issued to the herein-named applicant on August 23, 1955, of which this is a division.

In general, the primary purpose of this invention is to control the operation of a pressure operated member until a predetermined pressure condition becomes effective. Additionally, upon exhaustion of the operating condition, such as relieving gas pressure, the disclosed mechanism engages the movable member and prevents chatten ing usually present when a pressure condition subsides after relief.

A further object of the invention is to provide means, adjustable within a wide range of pressure limits, which is consistently capable of the requisite positive delay and control action.

" The invention consists of an engaging element and a latch means. These separate components are fixed, respectively, to movable and immovable elements of the mechanism with which they cooperate. In normal operation the engaging element is fastened to the movable component while the latch means is attached to the immovable member. Such an arrangement is shown by way of illustration in the accompanying drawing in which:

Figure 1 is a side elevational view, partly in section, showing the engaging and engaged positions taken on lines 1-1 of Figure 3.

Figure 2 is a front elevational view showing the pivotal supports and bracket structure.

Figure 3 is a plan view taken on lines 3-3 of Figure 1.

Figure 4 is a side elevational view showing the release operation.

Corresponding characters are employed throughout the drawings to indicate and refer to corresponding parts.

Figure 1 shows an assembly of the latch, partly in section, but enough of all the parts being shown to illustrate how the device is constructed and how its Works. As noted above the engager or engaging element is basically a bracket preferably fixed to the movable component 12, although not necessarily so. The connection is made by a bolt 14, or other adjustable fastening means, fitted into the component 12 through the adjusting slot 16 in the bracket 10. Mounted on the contact portion of the engager 10 is a roller 18, pivotally suspended by the projection 20 in engaging position for cooperation with the latching means generally indicated by the numeral 22.

The inclusive numeral 22 indicates that combination of elements which comprises the latch means here shown as fastened to a comparatively immovable member 30 for cooperating engagement with the engager 10. Two cooperating brackets 32-32, fastened to the member 30 as with bolts 34-34, support adjustable pivot members 36-36 as the means of rotatably engaging the movable elements of the latch means. The opposed pivot mem- Patented Oct. 14, 1958 ice bers 3636 form an axis about which the latch means rotates in the releasing movement and which supports the latch relatively immovable during the engaging movement. This distinction, together with the advantage of such an arrangement, will be apparent after reading the description of the operation.

Further reference is made to Figure l for a description of the elements comprising the latch means 22. In addition Figures 2 and 3 will be found helpful as they illustrate these elements in different views and will clarify the cooperating relationship, as well'as the construction. A base plate 38 drilled as at 4040 to receive the pivot members 3636 is the member designed to support the control and operating elements. Weights 42, variable with operating requirements, are detachably attached to the plate 38 as with screw bolts 44.

A latch 46, shown here as fashioned from a piece of thin spring metal strip being relatively stiff in two planes yet having considerable flexibility in the third, forms the mounting 48 and is positioned on the base plate 38 by the attaching screws 50. As illustrated, the latch mounting 48 is free to use the natural resilience and spring of the metal from which it is formed in the length above its anchorage on the baseplate. The portion of the mounting attached to the base plate is held firmly between the angular adjusting member 52 and the compression spring support 54. An adjusting screw 56 threadedly engages the adjusting member 52 and presses against the immovable member 30 aifording angular adjustment for proper operation.

To further adjust the engaging position of the latch 46, the compression spring support 54 is fashioned to roughly approximate the working angle of the latch support where it contacts the base plate 38. The compression spring 58 and the mounting stud 60 for the spring are then substantially positioned to receive the latch movement as a direct rather than eccentric thrust. A stiffener 62 is placed behind the spring steel mounting 48 in position to lend rigidity where needed to the latch, but also to remain clear of the operating movement.

In considering the operation of the described combination, the particular use for which this device is intended must be re-emphasized. As distinguished from the normal pressure release latch such as is found in springpressed ball detents found in cupboard door latches, an unlimited, indefinite pressure cannot be contemplated as the operating force. The mechanism illustrated is capable of, and is intended for, an accelerating device, primarily as illustrated in the previously mentioned Patent No. 2,715,909, issued August 23, 1955. In that patent the latch described here is used to delay the movement of a relief valve member until a predetermined pressure is reached, and to re-latch that movable valve member in a secure position when the force of the relieved pressure no longer exists. To vary the effective response of the latch described for application in the broad field of pressure relief, ease and accuracy of adjustment are required. The following description of operation will emphasize the particular effectiveness of the illustrated device under these conditions.

Figure 1 shows the relative positions of the engager element 10 and the latch means 22 in the engaged position. In dot and dash lines, the latch 46 and latch mounting 48 are shown moved to clear the engager roller 18 as the movable member 12 moves in the direction indicated by the arrow. In this engaging action, the frictionless roller surface moves the latch 46 out of the way by contacting the upper sloping surface. The latch movement, in addition to the flexing action of the spring steel mounting about the point of engagement with the base plate 38, is also transmitted to the compression spring 58. The portion of the mounting 48 stiffened by member 62 is flexed directly against the spring. By adjusting the V efiective spring compression, or changing springs to suit the purpose, it is obvious that considerable operating flexibility at this point can be achieved.

It appears to be further evident that this operation would be obtained if the mounting 48 were hinge connected to the base plate 38 rather than one continuous steel strip. With: the proper selection of the compression spring 58 such construction would be equally effective. Inthe preferred form, compression spring 58 is fashioned to have definite characteristics. It should provide minimum resistance to the relatching operation yet lift the weights 42 off the stop adjustment 56. Such structural limitation permits the device to rotate about axis of pivots 3636 before disengaging the elements 46- and 18 in the opening cycle.

There isno further motion of the latch means beyond the movement here described. during the engaging operation. The force being directed downwardly by the direction of movement of member 12, the pivotal movement of the latching means would also be downward. However, as this tendency is resisted by the adjusting screw 56: and the construction of the attached elements, the lower supporting portion of the latch means remains immovable.

When suificient pressure is accumulated to operate the movable member to an open position, however; the latch means readily releases the engager as shown in Figure 4. The predetermined pressure for the disengaging operation having been reached the upward movement of member 12, as indicated by'the arrow, rocks the latch means about the pivotal supports 36, until the engager escapes, as indi- 'cated above in discussing the characteristics of the spring 58.

By increasing or decreasing the weights 42, varying the effective lever arm of the weights about the pivotal axis and the weights themselves, adjusting the angle of contact with adjusting screw 56, changing the effectiveness of the compressive strength of spring SSfand altering the angle of engagement between the engager and the latch piece 46, almost any condition of operation can be pre-estab lished. Practically all of these changes of operating response can be made as a field adjustment after the basic mechanism, here described, is placed in operation.

As a result of the mechanism here disclosed, a wide variety of force operated devices depending on a sudden reduction of restraining force for acceleration can be better controlled. Further, exact control under Varying and varied pressure conditions is both possible and practical. And finally, theadjustments of which the elements are capable permit of' varying the engaging characteristics independently of those required for releasing which gives an instrument of wide flexibility under any operating requirement.

The invention claimed is:

1. Restraining means for devices having a pair of relatively movable parts comprising an engaging element and 4 a latching means, said means including a pivotally supported base adapted to be positioned in cooperating relation with the engaging element, interchangeable weights removably securable to said base to vary the releasing force, a latch member hingedly fastened to the base to extend into latching engagement with the engaging ele- 'ment, adjustable resilient means supported by said base in working alignment with said latch member to vary the engaging operation, and adjusting means cooperating with the pivoted base to adjust the operating position of the latch member.

2. Mechanism especially adapted to restrain from substantial movement an element subject to unbalanced fluid pressure until such pressure unbalance reaches a predetermined value and to then allow an accelerated movement of such element, said mechanism comprising an engager connectible with said element, a roller carried by the engager, and a latch the base of which forms an acute angle with an upwardly sloping side adjacent the engager; and latch actuating mechanism comprising a spring pressed arm. carrying the latch and tending to move the latch toward the engager; a pivotally suspendedweighted member upon which said spring pressed arm is swingable and which cooperates with the spring to move the latch toward the engager;. said roller underlying the base of the latch when said engager is not subject to upward movement by said unbalanced pressure, and when said engager is pulled upward by said unbalanced pressure exerting an upward pressure upon the latch, causing the roller to ride along the base and retract said latch and arm in opposition to said spring and weighted member and override the junction of the base with the sloping side of the latch to thereby release the engager from the latch and effect a sudden acceleration of the movement of the engager and also release the said latch mechanism to effect the return of the latch to said first named position.

3. The mechanism defined in claim 2 comprising also a stationary member from which said weighted member is pivotally supported, an adjustable member secured to said weighted member, and an adjusting screw threaded in the adjustable member and adapted to engage the stationary member in the movement of the latch toward the engager.

References Cited in the file of this patent UNITED STATES PATENTS 333,640 Kunze Jan. 5, 1886 736,714 Gendson Aug. 18, 1903 1,042,340 Gustafsson Oct. 22, 1912 1,532,212 Wilms Apr. 7, 1925 1,663,066 Von Felden Mar. 20, 1928 1,682,574 Kocsis Aug. 28, 1928 2,076,306 Weeks Apr. 6, 1937 2,097,596 McDougall Nov. 2, 1937 2,715,909 Patterson Aug. 23, 1955 

